Bonus personal story: my father once baked poppy seed muffins with an extra heavy measure of seeds (if he likes a flavor, he really likes it… when the recipe calls for 1 clove of garlic he adds 3…) and these muffins tasted great: I ate 3 at 6 am just before heading off to high school. By 11 am I could barely keep myself awake and I kept dosing off in classes, but I made it through the day and as soon as I got home I took a nap. Later that night when we were talking about our days, my dad said he could barely stay awake at work, and we both suddenly made the connection to those muffins.

It depends how much is on the bagel… and watch out for them pastries… “Poppy seed cake, bagels, muffins, and rolls did not contain sufficient quantities of poppy seeds to give rise to opiate positive specimens by U.S. Department of Defense (DOD) GC-MS cutoff levels (morphine = 4000 ng/mL, codeine = 2000 ng/mL), although a number of specimens were positive by National Institute on Drug Abuse (NIDA) cutoff levels (morphine and codeine = 300 ng/mL). However, ingestion of poppy seed streusel or Danish pastry led to confirmed morphine and codeine positive specimens, irrespective of the use of DOD or NIDA confirmation cutoff values.” Source: pubmed article